Update README.md

Author: caesarcai

README.md

@@ -63,8 +63,8 @@ para.max_iter  = 100;
 1. params : parameters for the algorithm.
 	* .max_iter : Maximum number of iterations. (default 50)
 	* .tol : Desired Frobenius norm error. (default 1e-5)
-	* .beta_init : Parameter for thresholding at initialization. (default 4*beta)
-	* .beta : Parameter for thresholding. (default 1/(2*nthroot(m*n,4)))
+	* .beta_init : Parameter for thresholding at initialization. (default 4\*beta)
+	* .beta : Parameter for thresholding. (default 1/(2\*nthroot(m\*n,4)))
 	* .gamma : Parameter for desired convergence rate. Value should between 0 and 1. Turn this parameter bigger will slow the convergence speed but tolerate harder problem, such as higher $p$, $r$ or $\mu$. (default 0.5)   
 	* .trimming : Determine whether using trimming step. (default false)
 	* .mu : Incoherence of underlying low rank matrix. Input can be in format of .mu = mu_max, or .mu = [mu_U, mu_V]. (default 5)